1. Field of the Invention
The subject invention relates to a shaft assembly, and more specifically to a bipot joint interconnecting a first shaft and a second shaft.
2. Description of the Prior Art
Steering shaft assemblies transmit the movement of a steering wheel through an indirect path to a steering gear. The shaft assemblies typically include at least a first shaft and a second shaft, connected by cardan joint, i.e., a universal joint. Cardan joints permit pivoting movement around a single point in space about two mutually perpendicular axis' that are also mutually perpendicular to a spin axis of the shaft at a 0° joint angle. It is desirable for the shaft assembly to maintain a high torsional stiffness, while keeping frictional loss to a minimum. In order to maintain the high torsional stiffness, the cardan joint must be de-lashed, i.e., remove the slack from the joint. Because most cardan joints utilized in the steering shaft assemblies are constructed using multiple pivot pins, the common solution has been to increase the precision of the parts, which drives up the cost to manufacture the shaft assembly.
A bipot joint utilizes a single pin to achieve the same relative movement between the first shaft and the second shaft as that of the Cardan joints. Typically, the bipot joint includes forming a cross-cut slot into the first shaft, and coupling a T-pin to the second shaft, with the transversely extending leg of the T-pin extending through the cross-cut slot to connect the first shaft and the second shaft. Accordingly, the second shaft is free to rotate about the T-pin axis and the first shaft is free to rotate around the perpendicular axis defined by the transversely extending leg of the T-pin, via the T-pin's freedom to slide on a surface of the first shaft. Like the Cardan style joint, the bipot joint must also be de-lashed, which increases the friction present within the bipot joint. Additionally, the bipot joint as described above is prone to wear.